Cattle Egrets in Hawaii

This is from the Hawaii Audubon Society:

"The extent to which this egret has fulfilled its purpose in reducing flies on cattle has never been measured empirically, but cattlemen insist the incidence of insect-born ailments on cattle has decreased where they are present (Telfair R.C.II 1994). They undoubtedly perform pest control services in consuming grasshoppers, crickets, centipedes, millipedes, moth and beetle larvae, cockroaches, frogs, toads, ticks, rats and mice. But they also devour small birds and the eggs and nestlings of larger birds including seabirds on islands. (Long,1981;Telfair, op cit)."

"Another problem with Cattle Egrets is their potential for transmitting parasites and disease organisms to livestock, domestic fowl, wild birds and people. In Florida, they were found to have viral encephalitis, mycoplasma (PPLO ) infections, and salmonellosis. Parasites included louse flies, mites, trematodes, cestodes, helminths, and nematodes (Telfair, R.C. II , 1994). In 1972, Gagne (1972) urged theState Board of Agriculture to invoke strong regulations on the introduction of birds quoting a book by John Davis listing wild birds susceptible to Newcastle’s Disease. Cattle egrets were included. Gooch (1977) in a letter from the State Department of Health to R. Walker of the Department of Land and Natural Resources reported nestling and juvenile egret samples positive for Salmonella. The concern is that this disease might spread to native birds (Rauzon et al, 2004).Upon its introduction in 1959, the Hawaii Audubon Society said, “Although some of us regard importations with some trepidation, it would seem that the Cattle Egret will not displace any of our native birds” (Anon 1959a). But for other reasons,it is clear now that this deliberate introduction was a mistake. A wildlife biologist has said, “In view of the various negative impacts associated with Cattle Egrets including predation on young endangered waterbirds, depredation on aquaculture organisms, as hazards to aviation, and vectors of disease, the location of rookeries is important to management” (Walker,1983)."

This is from August/September 2011...